telcom 2700/infsci 1071 wireless networksdtipper/2700/2700_slides1k.pdf · telcom 2700/infsci 1071...
TRANSCRIPT
1
TelcomTelcom 2700/INFSCI 1071 2700/INFSCI 1071 Wireless NetworksWireless Networks
David TipperAssociate ProfessorAssociate Professor
Telecommunications ProgramUniversity of Pittsburgh
[email protected]@mail.sis.pitt.eduhttp://www.sis.pitt.edu/~dtipper/2700.html
Slides 1Slides 1
Telcom 2700/INFSCI 1071 2
Course Goals
• Provide students a understanding of the structure, system aspects and protocols of wireless networks.
• The focus in on the generations of cellular networks, WirelessMANs, WirelessLANs, and Wireless PANs.
2
Telcom 2700/INFSCI 1071 3
Text and Grading
• Text: Mobile Communications 2nd edition, Jochen Schiller, Addison Wesley
also recommend• Principles of Wireless Networks A Unified Approach, K.
Pahlavan and P. Krishnamurthy, Prentice Hall, 2002. • Overview of wireless network architectures
– Will post many links to papers to fill in on newer developments• Grading
– Homework + Labs (2 or 3 labs) 25%– Midterm 25%– Final Exam 30%– Term Project 20%– Group or individual project that involves a wireless network
technology• Past Projects include
– Evaluation of battlefield WLAN implementation– WiMAX QoS planning techniques– Comparative evaluation of smart antenna techniques– Ad hoc extensions of cellular networks for disaster/fault recovery– Paper on Regulatory issues for software/cognitive radios– Paper on Health issues of wireless technology
Telcom 2700/INFSCI 1071 4
Course Outline
• Introduction (Ch 1)– Overview or wireless networks, applications and issues
• Wireless communication fundamentals (Ch 2 -3)– Frequencies, Propagation, Modulation and Antennas, (Ch 2, +
Notes)– Mitigation Techniques and Multiple Access (Slides + Ch 3)
• Wireless Wide Area Networks– Cellular Networks: (Slides + Ch 4)
• Voice oriented cellular (frequency reuse, traffic engineering, etc.• GSM, cdmaone• Data oriented cellular
– 2.5 G (GPRS) and 3G UMTS, cdma2000
– Satellite Networks (Ch 5)– Location Technology
3
Telcom 2700/INFSCI 1071 5
Course Outline
• Wireless Local Area Networks (Ch 7)– IEEE 802.11 standard and MAC layer
– Variations in a,b,g,n
• Wireless Personal Area Networks (Ch 7)– IEEE 802.15, Bluetooth– Zigbee and sensors
• Wireless Metro Area Networks (slides + notes)– IEEE 802.16 (WiMAX)
• Application Development and higher layer protocols (Ch 8, 10)
Telcom 2700/INFSCI 1071 6
Wireless Communication Systems
• Wireless Communication System: – Any electrical communication system that uses a naturally
occurring communication channel, such as air, water, earth.
• Examples: – Cell phone, Sonar, ground penetrating radar – Broadcast: (one way)
• Radio, TV, pagers, satellite TV, etc.
– Two Way: • walkie talkie, cell phones, satellite phones, wireless local
area networks, etc.
• Fundamentally different from wired networks
4
Telcom 2700/INFSCI 1071 7
Mobile vs. Wireless
• Wireless Communication System: – Any electrical communication system that uses a naturally
occurring communication channel, such as air, water, earth.• Mobile and Wireless are not interchangeable
Wireless vs. Mobile Examplesstationary computer, pay phonecalling card, call forwardingwireless local loop cell phone, laptop with WLAN
• Mobile wireless communication systems focus– Communicate over the air via radio-waves– Support some form of user mobility
• Examine how they are different from wired networks
Telcom 2700/INFSCI 1071 8
Wireless Issues
•• Wireless link implicationsWireless link implications– communications channel is the air
• poor quality: fading, shadowing, weather, etc. • data rate and coverage vary
– regulated by governments• frequency allocated, licensing, etc.
– limited bandwidth• low bit rate, frequency planning and reuse, interference
– power issues• Power levels regulated (safety issue), conserve mobile terminal
battery life– security issues
• wireless channel is a broadcast medium!
5
Telcom 2700/INFSCI 1071 9
Mobility Issues
• Mobility Types– User mobility : user can access network while mobile
• must handoff calls/connections in progress as user moves• track users as they move so they can receive info/calls
– Service mobility: user’s services follow them• Need to have authentication and services follow user
• Degree of Mobility – Geographic range
• ranges from a house/apartment to worldwide– Speed
• ranges from stationary to bullet train• cordless phone vs. cell phone
• Mobility portable device
Telcom 2700/INFSCI 1071 10
Device Issues
• Mobile Device Issues– Portability
• Device and accessories size and weight – Usability
• User characteristics (size, dexterity, knowledge, etc.)• Environment characteristics (Temperature, degree of mobility,
etc)• Device Characteristics
– startup time– data integrity and security– cpu speed and memory size– power supply – user interface (keypad, stylus, voice, etc.)
– Functionality (standalone, network dependent)– Connectability (always, partial, never)
• In general have a limited power supply, user interface and speed compared to stationary device
6
Telcom 2700/INFSCI 1071 11
Mobile Devices
Performance and CostPerformance and Cost
Pager• receive only• tiny displays• simple text
messages•two way pagers
Mobile phones• voice, data• simple text displays• simplified WWW
PDA/Smartphone• graphical displays• character recognition• WWW•Simple versions of standard applications
Palmtop• tiny keyboard• simple versions
of standard applications
Laptop and Tablet PC• fully functional• standard applications
Sensors,embeddedcontrollers
Telcom 2700/INFSCI 1071 12
Wireless NetworksWireless Networks
– Wireless Wide Area Networks (WWANs)• Cellular Networks :
– GSM, cdmaone (IS-95), UMTS, cdma2000 EVDO
• Satellite Networks: – Iridium, Inmarsat, GPS, etc.
– Wireless Metro Area Networks (WMANs)• IEEE 802.16 WiMAX
– Wireless Local Area Networks (WLANs)• IEEE 802.11, a, b, g, etc. (infrastructure, ad hoc)
– Wireless Personal Area Networks (WPANs)• IEEE 802.15 (Bluetooth), IrDa, Zigbee, sensor,
etc.
7
Telcom 2700/INFSCI 1071 13
Wireless NetworksWireless Networks
IEEE 802.16100 Mbps – 10GbpsMetro, suburb, campus 1-15 km
WMANs
IEEE 802.15 IrDa, BlueTooth, Zigbee
.1 – 1Mbps5-10 M around deviceWPANs
IEEE 80211a, b, g, etc.1-106 MbpsIn building, campus wide, subdivision wide,Range ~ 100 M per AP
WLANs
2G: GSM, cdmaone2.5G: GPRS, cdma 2000 1X-rtt3G: UMTS, cdma2000 1x-EDVO3.5G: HSPDAProprietary
2G: 9.6 – 45 Kbps,2.5G: 50 -300 Kbps3G : 50kbsp- 2Mbps 3.5G: .1 – 20 MbpsSatellite – 9.6 – 512Kbps
National, Continent wideWorldwide
WWANs
StandardsTypical ThroughputGeographic CoverageNetwork
Telcom 2700/INFSCI 1071 14
•• Mobile phone systemsMobile phone systems– Support communication to mobile users via wireless
radio channel– Fastest growing technical device EVER!
• Nokia sold over 120 million phones last year!• More cell phones than wired phones• More internet capable cell phones than PCs
– Variety of systems and standards: • Analog 1G : NMT, AMPS, TACS• Digital 2G: GSM, IS-95b (cdmaone),• 3G: UMTS, cdma 2000
– Scope of services and coverage areas growing• SMS, MMS, laptop data, etc.• Focus now on wireless data and location aware services
WWANs
8
Telcom 2700/INFSCI 1071 15
Cellular Network Architecture
• Cell : Area covered by 1 radio tower unit (base station) • Cellular Systems:
• provide wireless coverage to a geographic area with a set of slightly overlapping cells. Use a set of low power radio stations to provide coverage, each cell has different set of frequencies or codes, support handoff of mobile from one cell to another, trackmobile for incoming call
cell
Cell coverage, size and actually shape depends on local geography, powerlevel, cell site height, antenna type, etc.
Hexagonal idealized cell shape
Telcom 2700/INFSCI 1071 16
Cellular Network Architecture
Public Switched Telephone Network
BSC BSC
MSC MSC
GMSCHLR
Wired or Backhaul network
Wireless (radio)part
VLRVLR
AUC
• Cellular Network Components• Mobile Station (Terminal) – handset• Base Station (cell site)• Base Station Controller (BSC)• Mobile Switching Center (MSC)•Gateway MSC (interface to wired phone)• Home Location Register (HLR)• Visitor Location Register (VLR)• Authentication register (AUC) • HLR/VLR/AUC databases to track, bill and authentic users
Base Station
9
Telcom 2700/INFSCI 1071 17
2G Cellular Network Architecture
Telcom 2700/INFSCI 1071 18
Cell Phone MarketCell Phone Market
• Stratification of market• Teenage• Safety/children• Business – low end• Business – high end• Families• Luxury
• Improvements in • display technology• memory• cpu speed
• Smaller devices greater functionality merger with other portable devices or accessories
10
Telcom 2700/INFSCI 1071 19
2.5/3G/WLAN Mobile Devices• More Internet-friendly
interface– Wide, color screens
• More flexible to support new applications– Voice– Video telephony capabilities– Web browsing– Web Games– Electronic postcards– Location-based services– Streaming applications
• Various I/O modes/interfaces– Keypad, – voice recognition, – character recognition, – pen based, etc.
Telcom 2700/INFSCI 1071 20
Handset Market• Top Ten Phones in US during 1/01-10/30/07
– Motorola RAZR V3 – Motorola RAZR V3m – LG VX8300 – Apple iPhone– LG Chocolate VX8550/8500 – Motorola MOTOKRZR K1m – Samsung SGH-A707 – LG VX5300 – Sanyo Katana II – Motorola V323i/V325i
• Still a wide variety of phones and capabilities –high end PDA type phones minority
11
Telcom 2700/INFSCI 1071 21
Base StationsBase Stations
• Base Station (BS)Provides radio channels between mobile units and network
Pico-cells : (indoor – 0-.5 Km) support 8-20 channels
micro-cells: (outdoor – 0-1 Km), macro-cells: (1-30 Km)
Telcom 2700/INFSCI 1071 22
Base StationsBase Stations
• Base Transceiver Station (BTS) - houses radio units
12
Telcom 2700/INFSCI 1071 23
Base Station ControllerBase Station Controller
• Base Station Controller (BSC)Manages a cluster of BS, channel assignment, handoff, power control, some switching, etc
Telcom 2700/INFSCI 1071 24
Mobile Switching CenterMobile Switching Center
• Mobile Switching Center (MSC) (MTSO)
– Provides switching functions , coordinates location tracking, call delivery, handoff, interfaces to HLR,VLR, AUC, etc..
– Size of central office switch
13
Telcom 2700/INFSCI 1071 25
HLR/VLRHLR/VLR
• Home Location Register (HLR)
– Specialized database server contains billing info, service profile and general location of a mobile user (one per service provider or one per section of country)
– Visitor Location Register (VLR) similar to HLR contains location of users and their service profile of all users in a metro type area (one per MSC)
Telcom 2700/INFSCI 1071 26
WWANS - Satellites
• Over 3500 Satellites in use today - industry overall revenues of $2.3 billion in 2004
• Telecommunications– global telephone connections– backbone for global networks– connections for communication in remote places or
underdeveloped areas– global mobile communications
• Other Applications– weather – radio and TV broadcast satellites – Earth observation (climate change, agricultural, etc.)– military: surveillance, imaging, intelligence, early warning– Navigation and localization: aeronautic, nautical, etc., (e.g., GPS,
NavStar)
being replaced by fiber optics
14
Telcom 2700/INFSCI 1071 27
Satellite Basics
• Components• Earth (ground) Stations – antenna systems on or near
earth• Uplink – transmission from an earth station to a satellite• Downlink – transmission from a satellite to an earth
station• Typically separated frequencies for uplink and
downlink (FDD)• Transponder – electronics in the satellite that convert
uplink signals to downlink signals– transparent transponder: only shift of frequencies (Bent Pipe)– regenerative transponder: additionally signal regeneration and
formatting) Processing Satellite
Telcom 2700/INFSCI 1071 28
Typical Satellite System
footprint
base stationor gateway
Inter Satellite Link (ISL)
Mobile User Link (MUL) Gateway Link
(GWL)
small cells(spotbeams)
User data
PSTNISDN Cellular
GWL
MUL
PSTN: Public Switched Telephone Network
15
Telcom 2700/INFSCI 1071 29
Wireless MANs• Wireless Metropolitan Area Networks (WMANs) : provide wireless
connectivity across a geographical area the size of a city
Telcom 2700/INFSCI 1071 30
Wireless MANs
• Wireless Metropolitan Area Network (WMAN) – Wireless alternative to DSL/cable modem/Fiber to the
Home) services for last mile broadband access.– Point to Multipoint (PMP) protocol– Scope expanded to include mobility and higher data
rates – IEEE 802.16 standard– Worldwide Interoperability for Wireless Microwave
Access (WiMAX)• Both licensed and unlicensed spectrum
deployment• Advantages: cost, flexibility, mobility
16
Telcom 2700/INFSCI 1071 31
IEEE 802.16 /WiMAX Standard • Characteristics of 802.16
– Point to Multipoint (PMP) and Mesh protocol– NLOS wireless broadband services including bandwidth on
demand– QoS support – Security– Scope expanded to include mobility and higher data rates
• Focus on both licensed and unlicensed spectrum deployment – supports multiple service providers/licenses in same area
• 802.16 Terminology – Base Station (BS) is WiMAX cell site/access point– Subscriber Station (SS) is customer premise equipment and
terminates the wireless link to the user location– Mobile Station (MS) is a standalone consumer device equipped
with a WiMAX radio
Telcom 2700/INFSCI 1071 32
WiMAX Architecture
Line-of-Sight Backhaul802.16d
802.16
INTERNETBACKBONE
Telco Core Network or
Private (Fiber) Network
Non Line-of-SightPoint to Multi-Point
17
Telcom 2700/INFSCI 1071 33
WiMax Applications
• According to WiMax Forum it supports 5 classes of applications:
1. Multi-player Interactive Gaming.2. VOIP and Video Conference3. Streaming Media4. Web Browsing and Instant
Messaging5. Media Content Downloads
Basically the Triple Play
Telcom 2700/INFSCI 1071 34
Wireless LANsWireless LANs
•• Wireless Local Area Networks Wireless Local Area Networks – Support communication to mobile data users via
wireless channel– Types of WLAN
1. Infrastructure based (most popular)Connect users to a wired infrastructure network
Wireless access network like cellular phone system
IEEE 802.11, a, b, g , n
2. Ad-Hoc based networks– Provide peer to peer communication – mobiles communicate
between each other directly
– Rapid Deployment (conference room)
– IEEE 802.11, a, b, g , n, Proprietary
3. Point – to –Point (cable replacement!)
18
Telcom 2700/INFSCI 1071 35
Wireless Fidelity standards for InteroperabilityComponents: access points, antennas, mobile stations
- 300 manufacturers- www.wirelessethernet.org
WLAN components
Telcom 2700/INFSCI 1071 36
IEEE 802.11 Terminology
• Access Point (AP)– Provides access to distribution services via the wireless
medium
• Basic Service Area (BSA)– The coverage area of one access point
• Basic Service Set (BSS)– A set of mobile stations controlled by one access point
• Distribution system– The fixed (wired) infrastructure used to connect a set of BSS to
create an extended service set (ESS)
• Portal(s)– The logical point(s) at which non-802.11 packets enter an ESS
19
Telcom 2700/INFSCI 1071 37
WLAN Topologies
ad-hoc based architecture
BSS 1BSS 2
BSS 3
AP 1
AP 2
AP 3
WT 1WT 2
WT 3
WT 4
WT 5
ESS
Wired-distribution network
Basic Service Area (BSA)
Communication link
BSS = Basic Service SetESS = Extended Service SetAP = Access PointWT = Wireless Terminal
Infrastructure based architecture
Point-to-point
Telcom 2700/INFSCI 1071 38
Wireless Personal Area Network
• Origins in the BodyLAN project initiated by BBN in the early 1990s
• Networking “personal” devices – sensors, cameras, handheld computers, audio devices, etc. with a range of around 5 feet around a soldier
• Today: Networking digital cameras to cell phones to PDAs to laptops to printers to etc..,
• Most popular application – hands free headset to cellphone
• IEEE 802.15 standard (Bluetooth)– Use band available globally for unlicensed users– Low powered – medium data rate ~100s kbps– Subgroups doing higher data rates and sensors (Zigbee)
20
Telcom 2700/INFSCI 1071 39
Applications of WPANs
(a)(a) (b)(b)
(c)(c)
PSTN or the Internet
PSTN or the Internet
Cable Replacement
Ad hoc connectivity
Access to wired network
Telcom 2700/INFSCI 1071 40
Wireless NetworksWireless Networks
– Wireless Wide Area Networks (WWANs)• Cellular Networks :
– GSM, cdmaone (IS-95), UMTS, cdma2000 EVDO
• Satellite Networks: – Iridium, Inmarsat, GPS, etc.
– Wireless Metro Area Networks (WMANs)• IEEE 802.16 WiMAX
– Wireless Local Area Networks (WLANs)• IEEE 802.11, a, b, g, etc. (infrastructure, ad hoc)
– Wireless Personal Area Networks (WPANs)• IEEE 802.15 (Bluetooth), IrDa, Zigbee, sensor,
etc.
21
Telcom 2700/INFSCI 1071 41
Example Network Architecture
Laptops
Handheld PCs Switch & mobility and
radio resource management
Public Switched Telephone or Public
Data Network
Base Station
Multimedia terminal
WLAN
Switch
Access Point
Horizontal or Intra-tech Handoff
Vertical or Inter-techHandoff Router
LAN Segment
Cell
LEGEND WWAN
WPAN
Telcom 2700/INFSCI 1071 42
Evolving Applications
•• Focus on data based services and value added Focus on data based services and value added applicationsapplications–– Mobile Internet AccessMobile Internet Access–– Mobile Intranet/Extranet AccessMobile Intranet/Extranet Access–– Personalized InfotainmentPersonalized Infotainment
•• Video, audio, games, etc. Video, audio, games, etc.
–– Multimedia Message Service (MMS) Multimedia Message Service (MMS) –– Location Based Services (LBS)Location Based Services (LBS)–– Rich VoiceRich Voice
•• Theme Theme –– MultiMulti--mode (multimode (multi--media) servicemedia) service–– Community and identityCommunity and identity
Facebook Mobile
22
Telcom 2700/INFSCI 1071 43
Enablers
• Wireless network development– Increased bandwidth/data rate – Falling costs– Always on capability– WLAN – hotspots
• Mobile Devices– Fast development– More connectivity, computing power and autonomy, but lower
size, weight and cost– More functionality – camera, mms, radio, gps, compass
• Software Infrastructure– wap, xml, VXML, J2ME, .NET CF, Device emulators, etc.– Smart Clients
• mobile databases, synchronization technology• Standardization
– Software, protocols and hardware (e.g., Bluetooth). etc..
Telcom 2700/INFSCI 1071 44
Something doesn’t seem right. Am I testing the right circuit? This is the one I’mworking on.
Less experienced technician at field site #1.
No, that’s not the correctone. Scan to the left, I’ll tell you to stop whenyou get to the right spot.
Expert technician at field site #2.
Example: Expert on Call
Streaming Media, Real-time voice, Best Effort Data Convergence
Feasible with 3G technology
23
Telcom 2700/INFSCI 1071 45
Example Application
Marie buys a new phone. She is showing it to her friend Susie.
Marie gives names to positions. Marie leaves to work, surprised that her phone helped her not to be late.
The device has learnt where Marie likes to visit and what she does.
Look, it remembers!
I am going to teach my phone my
habits.
Your phone is beeping
Looks cool!
After one week…
Telcom 2700/INFSCI 1071 46
Summary
• Overview of Wireless Networks– WWANs (cellular, satellite)– WMANs (802.16 - wiMAX)– WLANs (802.11)– WPANs (802.15)
• Mobile Applications